RLM vs DB50X
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
RLM
This advanced scientific calculator emulates the functionality of the HP-15C, offering comprehensive tools for finance, business, statistics, and scientific calculations. It supports programming, equation solving, and unit conversions, optimized for iOS devices.
- Programmable advanced scientific calculator
- Finance and business calculation menus
- Statistics and probability functions
- Complex numbers and matrix operations
- Unit and currency conversions
- Equation solver and programming capabilities
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The RLM-15CX application is a programable advanced scientific calculator. It is based in the Hewlett-Packard HP-15C calculator, but specially designed to bring up the most of your iOS devices and , at the same time, conserving the easy of use and the functionality originally provided by the real calculator. >Finance Menu: •Account Balance: Credit line type account based on cash transactions and interest rates applied. •Amortization: Loan Amortization Schedule for a single loan payment or from several payments at once. •Bond Price & Yield: Bonds calculations in an easy way with all options and values at sight. •Black-Scholes Options: CALL, PUT and “Greeks” calculations of the Black-Scholes European option valuation model. •Equal Periods Cash Flows: Solve problems where different cash flows occur at regular time intervals. •Unequal Periods Cash Flows: Solve problems where different cash flows occur at different dates. •Depreciation: Calculates depreciation with SL, SOYD, DB or MACRS methods and conventions. values at sight. •Interest Rates: Nominal and effective interest conversion. •Time Value of Money: Compound Interest problems involving money earning interest over a period of time. >Business Menu: •Bill-Tip-Split: Calculates the sharing of a Bill with Tip. •Break-Even: Analyze the following relation: Profit = (Price - Var.Cost) • Units - Fix.Cost •Currency Exchange with on-line rates. •Percents & Margins: Calculates %Change, %Total and Business margins. >Date / Time Menu: Calculates Date and Time intervals with all values at sight. >Statistics Menu: •One-Variable Statistics: Calculations for one variable data samples. •Two-Variable Statistics: Calculations for two variables data samples. •Curve Fitting: 6 Regression models to fit a curve based on two variables data samples. •Probability: Combinations, permutations, Normal, Exponential, t-Student and Weibull probability distributions. >Scientific Menu: •Complex Numbers: Operations and functions with complex numbers. •Matrix: view, create or edit matrices with real or complex elements. •Plane Triangle: Solves a two dimensional triangle (ASA,SAS,SSA and SSS). •Spherical Triangle: Solves a triangle in a sphere’s surface (AAA,AAS,ASA,SAS,SSA and SSS). •Universal Constants: All the NIST-CODATA fundamental physical constants. •Vectors 3D: Operations and functions with vectors in Cartesian, Spherical or Cylindrical coordinates. >Convert Menu: •Angles & Polar: Convert angles between DEG,RAD,GRAD,DMS or Slope % & Polar-Rectangular coordinates. •Currencies: world currencies conversions with manual input or on-line current rates. •Interest Rates: Nominal and effective interest conversion. •Units: Physical units conversions. >Program Menu: Create, edit or load previously saved programs. >Solver Menu: Solve arbitrary algebraic equations entered and saved in the equation editor and creates a menu with all the variables to solve any of them. >Utilities Menu: •General Settings: Customize the calculator to your preference. •Memory Content: Shows all memory content edit, backup or restore. •Help Documents: learn by example about all menus. >Editors: submenu to select data editors. System requirements: iOS 15.0 or above. 30 days Free-Trial. In-App-Purchase: One-Payment for life. License Agreement: http://www.apple.com/legal/itunes/appstore/dev/stdeula Disclaimer: THIS IS NOT A HEWLETT PACKARD CALCULATOR, AND IS NOT SPONSORED IN ANYWAY BY HEWLETT PACKARD OR ANY OF ITS SUBSIDIARIES
DB50X
This scientific calculator offers high-precision computations with arbitrary precision for numbers. It supports advanced functions like complex numbers, matrices, symbolic calculations, and graphing, with a user-friendly interface and extensive built-in help.
- Arbitrary precision calculations
- RPN and algebraic operations
- Complex numbers, vectors, matrices
- Symbolic and numerical solving
- Graphing and plotting
- Engineering units and constants
- Unicode text support
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DB50X is a new high-precision scientific calculator inspired by the legendary HP50G series from Hewlett-Packard. It is not an emulator, but a redesign from scratch, which is faster, and delivers never seen before capabilities like computations in arbitrary precision. Like the original HP50G, DB48X supports an unlimited stack, RPN and algebraic operations, complex numbers, based numbers, vectors, matrices, text, symbolic computations, numerical solving and integration, graphing and plotting, statistics, engineering units, and well over 1000 built-in functions. It integrates a library of equations and constants covering mathematics, physics or chemistry. Using modern technologies, DB50X goes well beyond the original HP50G in many ways: - It is significantly faster, uses less memory, and features a higher-resolution 240x400 pixels graphical color display. - Integer and decimal values can have an arbitrarily large number of digits, so you can compute log(pi) with 200 digits in a few keystrokes. - The six function keys feature up to three function per key, giving quick access to up to 18 related functions at a time. - Complex numbers can mix and match polar and rectangular form. - Symbolic operations extend to complex numbers, vectors and matrices. - Based numbers can be in any base from 2 to 36, and support any number of bits, making it easy to emulate a 23-bit or 512-bit processor. - Text is represented using Unicode instead of the proprietary HP encoding, facilitating data exchange with the rest of the world. - Multiple graphs can be distinguished using colour patterns - Engineering units include all the modern evolutions of the SI system, and can be configured by the user, e.g. to integrate currency units with the exchange rate du jour. Converting between USD/hour and EUR/day has never been so easy! - A built-in hyperlinked help system documents functions simply by holding the corresponding key, and combine a quick start guide, a user manual and a reference manual. - Over 700K of memory is available for RPL programs. - Access to iCloud to save your program and edit them from your Mac. DB508X will run many user RPL programs designed for the HP48, HP49 or HP50 directly as is. However, since it is not an emulator, it will not run any HP binary object, and notably will not run HP50G games or anything involving system RPL. This is an early-access release. Please consult https://github.com/c3d/db48x/blob/stable/doc/5-Unimplemented.md for a list of commands that are not yet implemented. DB50X is part of a family of related calculators that include the black-and-white DB48X and the entry-level DB40X.
Screenshots
Verdict
The clearest difference is price: RLM at Free against DB50X's $9.99. DB50X's advantage is rating (5.0 vs 4.1) and in-app purchases (none vs 4). On ratings volume, update cadence, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
RLM is free to download; DB50X costs $9.99 up front. RLM sells 4 in-app purchases, starting at $0.49 per month. DB50X asks for nothing beyond the download.
DB50X holds the better App Store score, 5.0 against 4.1. Both are backed by a comparable volume of ratings — 17 and 8 respectively. Written reviews point the same way: 80% of RLM's written reviews are positive against 100% of DB50X's.
RLM ships an update monthly, DB50X every 3 weeks. The most recent releases landed on September 10, 2026 and September 7, 2026 respectively.
| Parameter | RLM | DB50X |
|---|---|---|
| Price | Free — better | $9.99 |
| Rating | 4.1 (17 ratings) | 5.0 (8 ratings) — better |
| Positive reviews | 80.0% of reviews | 100.0% of reviews — better |
| Number of ratings | 17 — better | 8 |
| Update frequency | Monthly | Every 3 weeks — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases — better | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 14.0 — better |
| Further details — not scored | ||
| Size | 6 MB | 7 MB |
| Age rating | 4+ | 4+ |
| Developer | R.L.M. Software | Christophe de Dinechin |
Customer experience
RLM
DB50X
In-app purchases
RLM
- Monthly Subscription$0.491 Month
- Semi-Annual Subscription$2.996 Months
- Annual Subscription$5.991 Year
- One-Time Purchase$9.99
DB50X
No in-app purchases









